Mounted sensor as vex-precision flat and straight as possible. Aligning robot to wall. Allowing for the 2 second calibration. We rotate robot clockwise 360 degrees then align to wall again. We got these values: Start: yaw=0 heading=0 rotation=0 1st 360: yaw=-3 heading=356 rotation=356 2nd 360: …

What’s worked for me is to multiply the readout by a constant around 1.2 percent. It’s very consistent in it’s error so that worked for us.

Is your sensor mounted on a piece of metal that is not completely straight?

Maybe try using a rubber link? With the inertial it is kind of difficult to use rubber links, you have to mount the sensor to a piece of metal and then mount that to the chassis with rubber links.

dont do that, vibrations will magnify with a rubber link and any collision will send it shaking, screwing up your reading

We have it sandwitched between 2 pieces of metal with some rubber mesh in between. Problem is not vibration, the numbers are super consistent and clean, there is no drift and no spikes. Just the internal math seems wrong. A full circle is always missing 3-4 degrees. Like I said, we spin it back and …

Simple solution is to just scale the values to 360. Multiply heading by 360/356.5 This is assuming that the error accumulates consistently throughout the turn so you should test 90 and 180 degree turns, expecting roughly 1 degree and 2 degree error respectively. Another recommendation is to test d…

Take the IMU off the robot and try doing a full factory cal [image] Full alignment procedure for Inertial sensor OFFICIAL Tech Support This procedure calibrates the accelerometers in the Inertial sensor and saves the result in non volatile memory. This procedure needs ve…

@jpearman : James, thanks as usual, factory calibration was the thing I was looking for (and I promise to get better at searching the forum). I did the factory calibration and it did not solve the strange issue. It is not a life-and-death situation (this is a test bot) but curiosity is high. I filmed…

Out of curiosity, try placing the inertial sensor in a new orientiation, ie, place the sensor so the cable is facing up or down. I am assuming you are using a get yaw method of some kind. The IMU sensor is unique in that it automatically will redefine what axis is “yaw” according to gravity. It is p…

A constant is indeed what we use as well and we actually love this sensor for its consistency. We also love it for its temperature correction (not sure if this is done at chip level or at VEX firmware level but it’s noticeably there) - rate sensors (basically accelerometers that sense spin) are noto…

Inertial Sensor not counting 360 degrees properly

VEX V5 Technical Support

jpearman December 6, 2020, 2:54am 7

Take the IMU off the robot and try doing a full factory cal